1. Field of the Invention
The present invention relates to an electronic parts installation device for mounting electronic parts such as a fine chip part and a large integrated circuit device on a printed board. To be specific, the present invention concerns a cassette control device which operates cassettes for supplying the electronic parts to parts taking-out positions.
2. Description of the Related Art
FIGS. 9 to 11 show a conventional electronic parts installation device.
As shown in FIG. 11, an electronic parts installation device 7, which mounts electronic parts on a printed board 13 serving as a work, includes a head 8 attached on a robot arm 9 and a cassette group 11 for supplying electronic parts.
At mounting positions ST1 to STM of the cassette group 11, a plurality of first to Mth cassettes (3-1), (3-2), . . . , and (3-M) are set in order from an end in such a way as to supply multiple kinds (=M) of parts to the head 8.
Among parts supplied to parts taking-out positions P1 of the first to Mth cassettes (3-1) to (3-M), necessary parts are sucked by sucking nozzles q2 of the head 8. The head 8 which sucks and holds the parts is driven and carried to a target mounting position of the printed board 13 by the robot arm 9, and the head 8 mounts the parts thereon.
The attitudes and shapes of the parts are checked by a recognizing device 10 during the driving and carrying operation until when the electronic parts are sucked and held by the head 8 and reach the target mounting position of the printed board 13. At this moment, when it is judged that an electronic part sucked by the sucking nozzle q2 is defective in shape, the part is discarded in a disposal unit 12.
FIG. 10 shows a fundamental configuration of the first to Mth cassettes (3-1) to (3-M). Each of the cassettes includes a mechanism section 5 and a control section 6.
The mechanism section 5 is constituted by a reel (5-3) for winding and storing a carrier tape R, on which parts to be supplied are packaged at predetermined intervals, and a carrying/unpacking section (5-2) which intermittently drives the carrier tape R taken out from the reel (5-3) toward the parts take-out positions P1 and unpacks component storing parts of the carrier tape R so that the sucking nozzles q2 suck and hold target parts stored in the component storing parts. Further, the carrying/unpacking section (5-2) has a cylinder device as a power source, and the carrying/unpacking section (5-2) is provided with a valve V for turning on/off the passage of compressed air for operating the cylinder device.
The control section 6 is constituted by a valve control section (6-2), which operates the valve V based on an instruction from the cassette control device 2 placed on the outside of the cassette, and a connector (6-1), which connects the cassette control device 2 and the valve control section (6-2) to transmit and receive signals.
To be specific, with respect to the operations of the cassettes (3-1) to (3-M) are performed as below, the connector (6-1) receives a command of operating the valve from the cassette control device 2, and the valve control section (6-2) turns on/off the valve V. The timing of turning on/off the valve V is controlled by two sensors a and k mounted on the valve control section (6-2). The valve V is turned on by the valve control section (6-2), and at the completion of transfer of parts in the carrying/unpacking section (5-2), the first sensor a is turned on and the valve V is turned off. After the valve V is turned off, the valved V is turned on again when the parts are taken out. When the carrying/unpacking section (5-2) returns to the original position, the second sensor b is turned on and the operation is completed.
Besides, of the cassettes (3-1) to (3-M), for some specific cassettes where parts are taken out by the sucking nozzles q2, it is necessary to provide operation commands for supplying another parts to the parts take-out positions P1. The contents of the operation command are different depending upon the shape of a handled part and the shape of the carrier tape for packaging the handled part.
As shown in FIG. 9, the conventional cassette control device 2 is constituted by sequence arithmetic means 15 for recognizing instruction information 14 supplied from a host controller 4, and storage means 16 in which programs are written.
If a plurality (=K) of operation patterns are available for each of the cassettes (3-1) to (3-M), programs for the plurality (:K) of operation patterns are written for each of the cassettes in the storage means 16. (M*K) programs are written in total.
Here, the contents of the instruction information 14 supplied from the host controller 4 consist of at least three items as follows:                Which cassette (specific cassette) of the first to Mth cassettes (3-1) to (3-M) stores a target part        Which nozzle is used to take out the target part of the specific cassette        Which operation pattern is used to operate the specific cassette        
The sequence arithmetic means 15 using the instruction information 14 as input information searches regions of each cassette of the storage means 16 and operates the specific cassettes according to operation pattern programs of the search result every time a target part of a specific cassette is taken out by the sucking nozzle.
In recent electronic parts installation devices, the sucking nozzles q2 mounted on the head 8 has increased in number to enhance production efficiency. Accordingly, the total number (=M) of cassettes mounted in the cassette group 11 has also increased.
In the conventional cassette control device 2, every time one cassette is added, one region where K operation pattern programs are written is added in the storage means 16. Thus, the storage means 16 requires a larger capacity.
Moreover, since the inexpensive sequence arithmetic means 15 with low capability is adopted, at selection of a program required to operate a specific cassette according to a target operation pattern, all the regions of the storage means 16 are always scanned in the same order to obtain a program required to operate the necessary specific cassette. Thus, the scanning requires a long time and high-speed processing is demanded under the current circumstances.